Parallelism Technique In C#

static void GenerateNumbers() {
    for (int i = 0; i < 10; i++) {
        Console.WriteLine("Method - Number: {0}", i);
        Thread.Sleep(1000);
    }
}
static void PrintCharacters() {
    string str = "ABCD";
    for (int i = 0; i < str.Length; i++) {
        Console.WriteLine("Method - Character: {0}", str[i]);
        Thread.Sleep(1000);
    }
}
static void PrintArray() {
    int[] arr = {
        1,
        2,
        3,
        4,
        5,
        6,
        7,
        8
    };
    foreach(int i in arr) {
        Console.WriteLine("Method3 - Array: {0}", i);
        Thread.Sleep(1000);
    }
}
static void Main(string[] args) {
    Parallel.Invoke(new Action(GenerateNumbers), new Action(PrintCharacters), new Action(PrintArray));
    Console.ReadLine();
}

Parallel.Invoke(() => {
    Console.WriteLine("Begin first task...");
}, () => {
    Console.WriteLine("Begin second task...");
}, () => {
    Console.WriteLine("Begin third task...");
});
Console.WriteLine("Returned from Parallel.Invoke");